I have one of those magnetic bandages (nikken) that close with velcro/scotch. It is for my elbow and I wear it a lot. After just a few months, the velcro is not catching. It was expensive and it took all my pain away. Can I resuscitate the velcro or should I patch it?
Sometimes the hook side (of the hook and loop as it is sometimes called) gets full of fuzz from the othe side. If you patiently pick it out with a needle or safety pin , it makes a big difference.
Scrub the velcro 'teeth' with an old toothbrush. This may get the lint out. This was a friend's suggestion. Worked for her.
All you have to do is hold a flame close {not too close though} to the fuzzy part of the velcro . This will cause the fuzzy part to curl up again . As soon as you see the threads curling move the flame away. You must keep the flame moving . Do this very quickly And you should restore some strength in your velcro
Buy velcro in a sewing store and replace it.
If you can't revive it with a toothbrush, you can get two kinds at the fabric store.....sew-on and the kind with a sticky back.